Choppy and the Princess (1967)

Princess Sapphire is a princess who was born with a boy's mind and raised as one because of one mischievous angel's mistake. Nevertheless, there is no way a girl can take the throne so her parents and the maid that helped raised her kept it a secret from everyone. Now as a Knight of Ribbon she has to fight to avoid having her identity revealed that Sapphire is a girl. She'll need the help of an angel who is in fact a make-believe angel.